JPS6314334B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exposure method. The present inventor previously proposed a technique that can be applied to a slit exposure type copying machine and its application equipment. The technique relates to a method for maintaining a predetermined distance between the document surface and the photoreceptor surface (hereinafter referred to as the basic technique), and is disclosed in detail in Japanese Patent Application No. 1983-99632.

The present invention is an improved technology regarding the above basic technology. Therefore, an overview of the above-mentioned basic technology will be explained to the extent necessary for understanding the present invention, and then the present invention will be explained.

The above basic technology can be summarized and expressed as follows.

In this method, a first pressure contact of an optical system support member is pressed against a belt-like or endless belt-like photoreceptor that is tensionably supported between at least two positions, and the photoreceptor in this pressure contact portion is brought into a non-pressure state. In comparison, the optical system support member is moved in a fixed scanning direction with respect to the photoreceptor in a stationary state while being supported by being pushed up or down by the first pressure contact, and fixedly moved along the fixed scanning direction. This is a method of maintaining a predetermined dimension between the document surface and the photoreceptor surface, in which the distance between the contact glass and the photoreceptor pressure contact portion set by the first pressure contact is managed with desired accuracy in a predetermined scanning range.

In FIG. 1, reference numeral 1 indicates an endless belt-shaped photoreceptor, which is wound between a fixed roller 2 and a tension roller 3. As shown in FIG. The tension roller 3 is constantly pulled by the action of a compressible spring whose one end is fixed to an immovable member, so that the photoreceptor 1 is always under an appropriate tension.

Next, a contact glass 5 for placing a document is fixed above the photoreceptor 1 along the scanning direction A so as to be parallel to the upper surface of the photoreceptor 1 .

Now, between the contact glass 5 and the photoreceptor 1, there is an optical system support member 6 that can support the optical system unit 8.
is intervening. The optical system support member 6 has an elongated block shape and is movable in the scanning direction A guided by a guide member (not shown), and has a rotatably supported roller at its lower end.
This roller, indicated by the reference numeral 7, presses against the photoreceptor 1 so as to push it up, and functions as a first pressure contact. Therefore, the distance d between the roller 7 and the contact glass 5 is guaranteed to be a constant value with high accuracy as long as the optical system support member 6 is translated in the constant scanning direction indicated by the arrow A.

The means for guiding the optical system support member 6 in the constant scanning direction indicated by the arrow A is a well-known means for moving the optical system support member 6 along a guide member (not shown) parallel to the direction indicated by the arrow A. Since this is realized by an appropriate configuration, detailed explanation will be omitted.

In this way, the basic structure of a slit exposure scanning device used in copying machines and the like is completed. Needless to say, the optical system unit 8 has the function of forming an image of the document placed on the contact glass 5 on the portion of the photoreceptor 1 that is in pressure contact with the roller 7, with a predetermined slit width. It is placed at a position that satisfies the optical conditions.

In the above configuration, the photoreceptor 1 may be brought into pressure contact with the photoreceptor 1 by pressing it down, for example, using the rollers 7.

During slit exposure scanning by moving the optical system support member 6, the contact glass 5 and the photoreceptor 1
is left at rest. When the optical system support member 6 finishes moving through the predetermined scanning range B, an electrostatic latent image is formed over the scanning range B. The photoreceptor 1 is then rotated to perform a copying process such as development and transfer. Note that during exposure scanning, an exposure lamp is required to illuminate the surface of the document, but this is omitted to avoid complication of the drawing.

By the way, the problems with the basic technology explained above are as follows.

During slit exposure scanning, as the optical system support member 6 is moved in the scanning direction A, the rollers 7 are also rotated and moved in the scanning direction A. 1 is moved in the scanning direction A due to the frictional force acting between it and the roller 7.
It receives a force in the direction of movement, and is moved slightly. In this way, if the photoreceptor 1 moves from its normal position even by a small amount, the image projected by the optical system unit 8 will be distorted, making it impossible to form a faithful latent image on the original.

SUMMARY OF THE INVENTION An object of the present invention is to provide an exposure method that can solve the above-mentioned problems that arise with the implementation of the above-mentioned basic technology.

Embodiments of the present invention will be described in detail below with reference to the drawings.

It should be noted that in the following explanatory drawings, in order to avoid complexity, the same reference numerals as those in FIG. 1 are used for parts that are unlikely to be confused.

The present invention is carried out by performing exposure in a state where rotation of the photoreceptor is forcibly prevented using a braking means.

FIGS. 2 and 3 show an embodiment in which the braking means is composed of a friction piece and a lever, solenoid, etc. that moves the friction piece toward and away from the surface of the photoreceptor. .

In the figure, reference numeral 9 denotes an elongated plate-shaped friction piece, which is located near the outer periphery of the fixed roller 2 and whose lower end is fixed to the support block 10. A shaft 11 that projects integrally with the support block 10 is pivotally supported by a stationary member (not shown), and the shaft end is fixed to the base end of the lever 12. The other end of the lever 12 is pivotally supported by one end of a link 13, and the other end of this link 13 is pivotally supported by a plunger 14a of a solenoid 14. Here, since the solenoid 14 is also fixed to a stationary member (not shown), the friction piece 9 is swung about the shaft 11 in accordance with the movement of the plunger 14a into and out, and presses the photoreceptor 1 against the fixed roller 2. , or release the pressed state.

For example, in the position of the friction piece 9 shown by the imaginary line in FIG. 3, the photoreceptor 1 is pressed by the friction piece 9 and its freedom of rotation is restricted, and if exposure scanning is performed in this state, the above-mentioned result will occur. Does not cause any problems.

After the exposure scan is completed, the photoreceptor 1 is rotated to perform processes such as development, transfer, and cleaning. This rotation is provided by a chain 16 wound around a sprocket 15 that is integrated with the shaft of the fixed roller 2. At this time, the solenoid 14 is activated to push out the plunger 14a and separate the friction piece 9 from the photoreceptor 1. I have to let it happen. The on/off control of the solenoid 14 can be performed, for example, by installing microswitches at the home position and stroke end of the optical system support member 6, respectively, and operating the solenoid 14 by the optical system support member 6 as the optical system unit moves. This is done based on the signal from the microswitch that is activated.

In addition, this type of electrophotographic copying machine generally has the following:
Although the cleaning blade is provided so as to be in sliding contact with the photoreceptor, this cleaning blade may have both the original cleaning function and the function as the braking means according to the present invention.

Next, FIG. 4 shows an embodiment in which the braking means is composed of a ratchet wheel provided integrally with the shaft of the roller supporting the photoreceptor, and a pawl etc. that can be freely engaged with and detached from the ratchet wheel. It shows.

In the figure, reference numeral 17 indicates a ratchet wheel, which is integrally attached to the shaft 2a of the fixed roller 2. or,
Reference numeral 17a indicates a pawl that can be freely engaged and detached from the ratchet wheel 17. Since the lower end of the pawl 17a is pivotally supported by an immovable shaft 18, when the lever 19 pivotally attached to the pawl 17a is reciprocated in the direction of the arrow, the pawl wheel 17 moves in conjunction with this movement. It is locked or unlocked by 17a. The above-mentioned movement to the lever 19 may be applied, for example, by a solenoid or the like.

Although the above-mentioned configuration ensures reliable braking of the fixed roller 2, there remains some concern regarding slippage between the fixed roller 2 and the photoreceptor 1. In that case, protrusions 20 are formed at equal intervals on the circumferential surface of the fixed roller 2,
Further, a hole 21 is formed in the photoreceptor 1 corresponding to this protrusion 20.
If the protrusion 20 and the hole 21 are left open and the protrusion 20 is engaged with the hole 21, the above-mentioned concern regarding slipping can be solved. Alternatively, instead of using the structure of the protrusions 20 and holes 21, a material with a large friction coefficient may be selected as the surface material of the fixed roller 2.

Next, FIG. 5 shows an embodiment in which the braking means is constituted by a one-way clutch mounted on the shaft of the roller supporting the photoreceptor.

In the figure, reference numeral 22 indicates a one-way clutch, which is provided between the shaft 2a of the fixed roller 2 and the side plate 23. The one-way clutch 22 prevents the fixed roller 2 from rotating during exposure scanning. The rotation of the photoreceptor 1 during processes such as development, transfer, and cleaning is provided by a chain 25 and a sprocket 26 that are constantly rotating via a clutch 24 that is turned on and off depending on the process. The direction of rotation is set to be opposite to the direction of co-rotation (scanning direction A). Therefore, it can be said that this embodiment is truly suitable for the use of the one-way clutch 22 that allows rotation in only one direction.

By applying each of the braking means described above, movement of the photoreceptor during exposure scanning is prevented, and a latent image faithful to the original can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a front view of an exposure device section illustrating a technique for maintaining a predetermined dimension between a document surface and a photoreceptor surface, which is implemented in conjunction with the present invention, and FIG. 2 is a front view of an exposure device section showing an embodiment of the present invention. 3 is a front view of the same as above, FIG. 4 is a perspective view of an exposure device section showing another embodiment of the present invention, and FIG. 5 is a portion near the fixed roller showing still another embodiment of the present invention. FIG. 1... Photoreceptor, 5... Contact glass, 7...
...Roller (as the first pressure contact), 12... Lever, 14... Solenoid, 17... Ratchet wheel, 17a
...Claw, 22...One-way clutch.

Claims (1)

[Scope of Claims] 1. A first pressure contact of an optical system support member is pressed against a belt-like or endless belt-like photoreceptor that is tensionably supported between at least two positions, and the photoreceptor in this pressure contact portion is Compared to the non-pressure welding state, the above first
The optical system support member is moved in a fixed scanning direction with respect to the photoreceptor in a stationary state while being supported by being pushed up or down by a pressure contact, and is fixedly set along the fixed scanning direction. A method of exposing while controlling the distance between the contact glass and the photoconductor press-contact portion by the first press-fitting member with desired precision in a predetermined scanning range, the method comprising forcing rotation of the photoconductor using a braking means. An exposure method characterized by performing exposure in a state where the exposure is blocked. 2. An exposure method in which the braking means according to claim 1 is constituted by a friction piece, and a lever, solenoid, etc. that moves the friction piece toward and away from the surface of the photoreceptor. 3. An exposure device in which the braking means as set forth in claim 1 is constituted by a ratchet wheel provided integrally with the shaft of a roller supporting the photoreceptor, and a pawl or the like that can be freely engaged with and detached from the ratchet wheel. Method. 4. An exposure method in which the braking means according to claim 1 is constituted by a one-way clutch provided on the shaft of a roller supporting the photoreceptor.